This invention relates to the field of portable traffic control systems for use at temporary locations on streets and highways. More specifically, the invention relates to the trailer structure for transporting and erecting such traffic control signals.
In the construction and transportation industries there has long been a requirement for portable traffic control systems that can be located on or adjacent to highways and city streets. These signals are required where road construction is underway and requires that traffic be temporarily rerouted or traffic flow be controlled. Such apparatus is also necessary when permanent signal installations have been damaged or otherwise rendered inoperable, thus requiring some temporary traffic control while repairs are being effected. An alternative to portable systems is the use of flag personnel or traffic officers, who would have to be present 24 hours a day, thus requiring a substantial investment in manpower.
Several portable traffic signals have been found in the prior art, and some of them have filled some of the basic needs for such units, although all have been found wanting in one or more areas. Most of these prior art units fail to meet highway department standards in various states and are not effective for their intended purpose. Certain of these prior art units provide a signal only at the side of the road and do not include the inportant signal positioned over the roadway for increased visibility. One unit, disclosed in Woudenberg, U.S. Pat. No. 4,616,225, overcomes a number of these disadvantages and provides a signal head both at the side of the road and positioned over the road. However, the Woudenberg structure, by its basic configuration, requires that it be assembled and disassembled from the support each time the unit is to be transported and erected. To prepare this unit for operation, each of the two signal heads must be removed from their carriers on the trailer and attached to the operating supports. These supports are then raised and extended into position. Such assembly and disassembly is time consuming and presents additional opportunities for dropping or otherwise damaging the signal head.